Field of the Invention
The present invention relates to a damping structure capable of reducing vibration transmitted from one frame to another frame fixed with each other and to a damping component.
Description of the Related Art
Lately, frames such as a casing are formed of a thin metal plate or the like to lighten a weight of various products such as office equipment, e.g., a printer, home appliances, e.g., a refrigerator, automobiles and construction materials. If such frames are fixed with each other and if one frame is vibrated by an exciter such as a motor, there is a case when the vibration is transmitted to the other frame and the other frame generates radiation sound. Then, in order to prevent the radiation sound caused by the vibration from being generated, Japanese Unexamined Patent Application Publication Nos. 2014-95441 and 6-213277 propose to interpose vibration-proof rubber between the frames to suppress the propagation of the vibration among the frames.
A vibration-proof bush described in Japanese Unexamined Patent Application Publication No. 2014-95441 is configured such that a vibration-proof rubber member is interposed between a body panel and a sub-frame, and the body panel is connected with the sub-frame through the vibration-proof rubber member. However, because the vibration-proof rubber member is formed of soft rubber whose rigidity is low as compared to the frame, the vibration-proof rubber member is liable to deform between the body panel and the sub-frame. Therefore, relative positions of the body panel and the sub-frame are hardly determined to one position due to the deform condition of the vibration-proof rubber member and are changeable at each occasion. That is, the body panel and the sub-frame are liable to cause a positional shift. If the positional shift occurs in a case when a gear engaging with a gear provided on the sub-frame is provided on the body panel, disalignment of the gears occurs, and vibration and noise caused by the engagement condition of the gears is generated.
A vibration-proof bushing described in Japanese Unexamined Patent Application Publication No. 6-213277 is configured to attach an outer cylindrical portion formed of rubber to a bracket to suppress vibration transmitted from an attached member to the bracket. The bracket is interposed between the outer cylindrical portions and is caused to adhere only the outer cylindrical portion. In other words, the bracket and the attached member are connected by the outer cylindrical portion. Due to that, the bracket and the attached member are liable to cause a positional shift depending on a deformation condition of the outer cylindrical portion. In this case, the bracket and the attached member are liable to cause a positional shift because the outer cylindrical portion is adhered to the bracket by being compressively deformed by a screw. If the bracket and the attached member cause the positional shift, vibration and noise caused by the engagement state of the gears described above can be generated.